Extendable guidewire for cardiovascular procedures

ABSTRACT

An extendable guidewire system for introducing a dilatation catheter into the cardiovascular system. The guidewire has guidewire and extension sections with a connection therebetween which permits the two sections to be joined together and separated simply by pushing the two sections together and pulling them apart. One of the sections can be used for positioning the catheter within the cardiovascular system, and the other section can be employed to extend the wire to change catheters.

.Iadd.This application is a continuation, of application Ser. No.07/697,780 filed May 9, 1991, now abandoned. .Iaddend.

BACKGROUND OF THE INVENTION

This invention generally relates to cardiovascular procedures such asangioplasty, angiography and valvuloplasty, and more particularly to anextendable guidewire for use in such procedures.

Guidewires are currently used to facilitate the placement of cathetersin the arterial system of a patient for cardiovascular procedures suchas angioplasty, angiography and valvuloplasty. The guidewire istypically on the order of 20-50 cm longer than the catheter to permitthe guidewire and the catheter to be advanced relative to each other asthey are steered into position within the patient's body. Suitableguidewires are described in U.S. Pat. No. 4,538,622 (Samson et al.) andU.S. Pat. No. 4,569,347 (Frisbie) which are hereby incorporated hereinin their entirety.

In the usual procedure to change catheters, the guidewire is removedfrom the patient, and an exchange wire is inserted in its place. Thein-place catheter is removed from the patient and a new catheter isinserted into the patient. The exchange wire is then removed and theguidewire is reinserted. The exchange wire is substantially longer thanthe guidewire, and it generally extends outside the patient's body for adistance greater than the length of the catheter. With a dilatationcatheter having a length on the order of 120-140 cm, for example, aguidewire might have a length on the order of 175 cm, and an exchangewire might have a length on the order of 300 cm. The use of an exchangewire has the obvious disadvantage that it complicates the angioplastyprocedure.

Heretofore, there have been some attempts to eliminate the need for aseparate exchange wire by attaching an extension wire to a guidewire toextend the length thereof. The two wires are joined together by acrimped connector which requires a special tool. Once the wires havebeen crimped, the connection therebetween is permanent, and theextension wire cannot be removed except by severing it from theguidewire.

What has been needed and heretofore unavailable is an extension whichcan be readily connected and disconnected to the guidewire when it is inposition within the patient. The present invention satisfies this need.

SUMMARY OF THE INVENTION

The present invention provides a new and improved guidewire system andthe method of using the same.

In accordance with the present invention, a guidewire is provided withmain and extension sections which are detachably secured together bypress fitting. One of the guidewire sections has a tubular portion atthe connecting end thereof, and the other guidewire section has aconnecting end portion which has an effective diameter in one radialdimension which is slightly larger than the inner diameter of thetubular portion. The slightly larger connecting end of one of theguidewire sections is inserted into the tubular end of the otherguidewire section. One or both of the connecting ends are deformed toprovide an interference or friction fit therebetween and therebydetachably secure the two guidewire sections together. The two sectionscan be readily separated by pulling them apart. The two sections can bereconnected and disconnected as desired.

In the presently preferred embodiment, the end portion of the male endof the connection has an undulating shape which is adapted to beinserted into the tubular end of the guidewire section. The effectivediameter of the undulating portion should not be more than 50% greaterthan the inner diameter of the tubular member to facilitate theinsertion and removal thereof from the tubular member.

These and other advantages of the invention will become more apparentfrom the following detailed description thereof and the accompanyingexemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, centerline sectional view of an extendableguidewire embodying features of the invention, with parts separated;

FIG. 2 is a fragmentary centerline view of the embodiment shown in FIG.1 with the parts joined;

FIG. 3 is a cross-section view taken along lines 3-3 of FIG. 2; and

FIG. 4 is a partial centerline sectional view of an alternativeembodiment.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1-3, the guidewire system 10 embodying featuresof the invention has a main section 11 which is adapted to be insertedinto a patient's vascular system and an extension section 12 which canbe connected and disconnected to the main section 11 to facilitate theexchange of catheters without the need for removing the main section 10from the patient's vascular system. Main guidewire 11 generallycomprises an elongated shaft 13 with a flexible tip (not shown) at itsdistal end and a smaller diameter portion 14 at its proximal end whichis shaped into an undulating or sinusoidal shape. Reference is made toU.S. Pat. No. 4,538,622 (Samson et al.) and U.S. Pat. No. 4,569,347(Frisbie), which have been previously incorporated herein by reference,for a description of desirable guidewire tip constructions. Extensionsection 12 has an elongated shaft 16 with smaller diameter projection orpost 17 at its distal end.

The connection 18 between guidewire sections 11 and 12 generallycomprise tubular member 19 which is fixed to the distal end of the mainsection 12 and which receives interfitting undulating member 14 which ison the proximal end of section 11. Tubular member 19 is mounted bysuitable means such as welding, brazing, or the like onto the shortaxial extension 17 of reduced diameter at the distal end of shaft 16.Axial extension or post 17 can be formed by any suitable means such asgrinding down the proximal end portion of the shaft 16 to the desireddiameter so that it interfits into the end of tubular member 15. Theundulating portion 14 is formed by first grinding the proximal end ofmain section 11 to a smaller diameter, then forming the undulations orsinusoidal shape by bending over a mandrel or other suitable means. Themaximum effective dimension A of the undulated section should beslightly more than the inner diameter B of tubular connecting piece 17but preferably not more than 50% greater than dimension B to provideinterference or friction fit which will hold the sections togetherduring catheter exchange but which can be readily disengaged afterexchange has been made. Preferably no more than a one pound pull shouldbe necessary for disengagement.

In a guidewire having a diameter on the order of about 0.014 inch, forexample, tubular member 19 might have an inner diameter of about 0.007inch and a wall thickness on the order of 0.001 inch and the undulatingsection 14 might have a maximum effective radial dimension of about0.009 inch. In this embodiment, tubular member 19 might have a length onthe order of about 2.4-2.5 cm.

The main guidewire section is intended for use in positioning adilatation catheter (not shown) in the cardiovascular system of apatient, and it has a length corresponding to the length of aconventional guidewire for this purpose. Details of typical dilatationcatheters and guidewires can be found in the patents cited previouslyand incorporated herein.

Extension section 12 is sufficiently long so that when the guidewiresections 11 and 12 are connected together the guidewire system 10 has anoverall length suitable for exchanging catheters without removing themain section 11 from the patient's vascular system. With a dilatationcatheter having a length on the order of 120-140 cm, for example,section 11 might have a length of 140-175 cm, and section 12 might havea length of 125-160 cm.

Shafts 13 and 16 and tubular member 19 can be fabricated from suitablematerial, such as stainless steel, Nitinol (55% NI-Bal. Ti), and thelike, and each should have a diameter to allow a dilatation catheter topass freely over them. It is perferably that the two shafts 13 and 16 beof substantially the same diameter in order to provide a smoothtransition between them. In one presently preferred embodiment for usein coronary angioplasty, shafts 13 and 16 have a diameter on the orderof about 0.014 inch. Either or both of the shafts can be provided with acoating of polytetrafluoroethylene, which is sold under the trademarkTeflon by the DuPont Corporation, or another suitable low-frictionmaterial to facilitate the movement of the catheter over the wire.

An alternative embodiment is shown in FIG. 4 wherein the proximal end ofmain guidewire section 12 which is adapted to be inserted into thetubular member 19 is provided with a smaller diameter portion 30 havingprotrusions 31 which provide the interference or friction fit toreleasably secure together the sections 11 and 12 of the guidewiresystem 10. The protrustions can have various shapes such as thesemi-spherical shapes shown in FIG. 4, triangular shapes, or othershapes which may provide a suitable fit.

In use, the main guidewire section 11 is introduced into the vascularsystem of a patient with a dilatation catheter through a guidingcatheter not shown) and an introducer (not shown). When performingcoronary angioplasty, the distal end of the guiding catheter ispositioned in the coronary ostium, and the dilatation catheter isadvanced so that it is just proximal to the tip of the guidingcathether.

The distal tip of the guidewire is advanced beyond the distal tip of thedilatation catheter while the latter is held in place. As the mainguidewire section 11 is advanced, it is rotated and steered into theselected artery. The guidewire tip is preferably advanced through thelesion and beyond it, in order to permit the balloon portion of thedilatation catheter to be positioned within the lesion over a moresupportive section of the guidewire. Once in position, the mainguidewire section 11 is held in place and the dilatation catheter isadvanced along it until the inflatable balloon thereof is within thelesion. Undulating end portion 14 remains outside the patient's body andoutside any adapter which may be connected to the proximal end of thedilatation catheter.

To exchange catheters, the main guidewire section 11 is extended bymanually pressing the open end of tubular member 19 on the distal end ofextension section 12 onto the undulating end 14. As the tubular member19 is inserted over the undulating end 14, either the tubular member 19or the undulating member 14 or both deform to thereby firmly butreleasably hold the two guidewire sections together. The dilatationcatheter can then be withdrawn from the patient's body over the extendedguidewire system.

A new dilatation catheter may then be introduced over the extensionsection 12 and advanced along the main guidewire section 11 within thepatient's body until the balloon crosses the lesion. Once the proximalend of the new balloon catheter has advanced beyond connection 18 andtubular end portion 19, section 12 can be removed by grasping the twoguidewire sections 11 and 12 on opposite sides of the connection 18 andpulling them apart without disturbing the position of section 11 in thepatient's body. As previously described, the interference or frictionfit between the undulating member 14 and the tubular member 19 should besufficiently strong to hold the two guidewire sections 11 and 12together while dilatation catheters are being exchanged, but should becapable of separation by a pulling force less than one pound.

The invention has a number of important features and advantages. The twosections of the guidewire can be connected together whenever a longerwire is needed, and they can be separated whenever the additional lengthis not required. The two sections of the guidewire may be connected anddisconnected by the physician by simply pressing them together andpulling them apart. This can be done as needed, and no special tools arerequired either to make the connection or to separate it. Thus thecatheter exchange is greatly simplified.

It is apparent from the foregoing that a new and improved extendedguidewire system and method of using the same have been provided. Whilethe present invention has been described herein with the tubularconnecting element fixed to the distal end of the guidewire extensionsection and the male member adapted to be inserted into the open end ofthe tubular member on the proximal end of the main guidewire section, itis obvious that the tubular element on the distal end of the extensionsection may be interchanged with the male member on the main guidewiresection. Moreover, it will be apparent to those familiar with the art,that other modifications and improvements can be made without departingfrom the scope of the invention as defined by the following claims.

What is claimed is:
 1. An extendable guidewire system comprising:(a) amain guidewire section adapted to be inserted into a patient's vascularsystem which has a mating end adapted to extend out of the patient; (b)a guidewire extension section having a mating end; and (c) a connectiontherebetween suitable for repetitive connections including a tubularmember on the mating end of one of the guidewire sections having an openend, a male member on the mating end of the other guidewire sectionwhich is adapted to be manually inserted into the open end of thetubular member and means to releasably secure the two sections togetherby frictional engagement between the tubular member and the male member.2. The extendable guidewire system of claim 1 wherein the tubular memberis fixed to the mating end of the guidewire extension section and themale member is on the mating end of the main guidewire section.
 3. Theextendable guidewire system of claim 1 wherein the tubular member isfixed to the mating end of the main guidewire section and the malemember is on the mating end of the guidewire extension section.
 4. Theguidewire extension system of claim 1 wherein the tubular member isfixed to an end of a guidewire section by welding.
 5. The guidewireextension system of claim 1 wherein the tubular member is fixed to anend of a guidewire section by brazing.
 6. The guidewire extension systemof claim 1 wherein the male member has protrusions on the outer surfacethereof which engage the inner surface of the tubular member to therebyreleasably secure the two guidewire sections together.
 7. The extendableguidewire system of claim 1 wherein the male member has a diametricaldimension slightly larger than the inner diametrical dimension of thetubular member receiving the male member so that upon the insertion ofthe male member into the tubular member the guidewire sections arereleasably secured together.
 8. The extendable guidewire system of claim7 wherein the male member is provided with an undulated shape.
 9. Theextendable guidewire system of claim 7 wherein the maximum diametricaldimension of the male member is not more than 50% greater than theinside diameter of the tubular member.
 10. A method of using anextendable guidewire system in a vascular procedure, said guidewiresystem having a main guidewire section with a mating end, a guidewireextension section with a mating end, and a connection therebetweensuitable for repetitive connections comprising a tubular member havingan open end on one of said mating ends of the guidewire sections, a malemember on the mating end of the other section which is adapted to beinserted into the open end of the tubular member and means to releasablysecure the interconnected ends together, the method comprising the stepsof:(a) percutaneously introducing a main guidewire section into thevascular system of a patient with the mating end thereof extendingoutside the body of the patient; (b) advancing a first catheter over themain guidewire section within the vascular system; (c) releasablysecuring the mating end of the extension guidewire section to the matingend of the main guidewire section by manually inserting the male memberon one of the guidewire sections into the tubular member on the otherguidewire section so that the interconnected ends are releasably securedtogether by frictional engagement between the tubular member and themale member; (d) withdrawing the first catheter from the vascular systemof the patient over the two interconnected guidewire sections; (e)introducing a second catheter into the patient's vascular system overthe two interconnected guide sections; and (f) disengaging the extensionguidewire section from the main guidewire section by manually pullingthe two guidewire sections apart with the main guidewire sectionremaining in place in the vascular system of the patient. .Iadd.
 11. Anextendable guidewire system for multiple catheter exchanges,comprising:a. a main guidewire section adapted to be inserted into apatient's vascular system, said guidewire section having a mating endadapted to extend out of the patient; b. a guidewire extension sectionhaving a mating end; and c. connecting means for repetitive connectionsbetween said main guidewire section and said extension section bynon-permanent deformation of either of said mating end whereby saidextension wire section and said main guidewire section can berepetitively connected and disconnected. .Iaddend. .Iadd.12. Theextendable guidewire system of claim 11 wherein the maximum diameter ofsaid connection means, after connection, is substantially the samediameter as that of said main guidewire section. .Iaddend. .Iadd.13. Theextendable guidewire system of claim 11 wherein one of said mating endsis composed of elastically deformable material. .Iaddend. .Iadd.14. Theextendable guidewire system of claim 11 wherein said connecting meansincludes a tubular member on the mating end of one of the guidewiresections, said tubular member having an open end, and a male member onthe mating end of the other guidewire section. .Iaddend. .Iadd.15. Theextendable guidewire system of claim 14 wherein said male member isadapted to be inserted into said open end of said tubular member..Iaddend. .Iadd.16. The extendable guidewire system of claim 14 whereinsaid tubular member and said male member are releasably secured at theirmating ends by frictional engagement. .Iaddend. .Iadd.17. An extendableguidewire system for multiple catheter exchanges, comprising:a. a mainguidewire section adapted to be inserted into a patient's vascularsystem, said guidewire section having a mating end adapted to extend outof the patient; b. a guidewire extension section having a mating end; c.connecting means for detachably joining said mating end of said mainguidewire section to said mating end of said guidewire extensionsection, said connecting means including a tubular member on the matingend of one of the guidewire sections, said tubular member having an openend, and a male member on the mating end of the other guidewire sectionadapted for slidable insertion into said tubular member; and d. saidconnecting means having a maximum diameter, after connection, no greaterthan the maximum diameter of said tubular member. .Iaddend. .Iadd.18. Anextendable guidewire system for multiple catheter exchanges, comprising:a. a main guidewire section adapted to be inserted into a patient'svascular system, said guidewire section having a mating end formed by atubular member adapted to extend out of the patient; b. a guidewireextension section having a mating end; c. connecting means fordetachably joining said mating end of said main guidewire section tosaid mating end of said guidewire extension section; and d. saidconnecting means having an overall maximum diameter, after connection,no greater than the maximum diameter of said tubular member. .Iaddend..Iadd.19. An extendable guidewire system for multiple catheterexchanges, comprising:a. a main guidewire section adapted to be insertedinto a patient's vascular system, said guidewire section having a matingend adapted to extend out of the patient; b. a guidewire extensionhaving a mating end formed by a tubular member; c. connecting means fordetachably joining said mating end of said main guidewire section tosaid mating end of said guidewire extension section; and d. saidconnecting means having an overall maximum diameter, after connection,no greater than the maximum diameter of said tubular member. .Iaddend..Iadd.20. An extendable guidewire system for multiple catheterexchanges, comprising:a. a main guidewire section adapted to be insertedinto a patient's vascular system, said guidewire section having a matingend formed by a tubular member adapted to extend out of the patient; b.a guidewire extension having a mating end; c. connecting means fordetachably joining said mating end of said main guidewire section tosaid mating end of said guidewire extension section; and d. at least aportion of said connecting means having an overall maximum diameter,prior to connection, greater than the inside diameter of said tubularmember. .Iaddend. .Iadd.21. An extendable guidewire system for multiplecatheter exchanges, comprising: a. a main guidewire section adapted tobe inserted into a patient's vascular system, said guidewire sectionhaving a mating end adapted to extend out of the patient; b. a guidewireextension having a mating end formed by a tubular member; c. connectingmeans for detachably joining said mating end of said main guidewiresection to said mating end of said guidewire extension section; and d.at least a portion of said connecting means having an overall maximumdiameter, prior to connection, greater than the inside diameter of saidtubular member. .Iaddend. .Iadd.22. The extendable guidewire system ofclaim 21 wherein one of said mating ends has a diametrical dimensionlarger than the inner diametrical dimension of the other said mating endso that upon insertion of one mating end into the other mating end thecorresponding guidewire sections are releasably secured together..Iaddend. .Iadd.23. An extendable guidewire system for multiple catheterexchanges, comprising:a. a main guidewire section adapted to be insertedinto a patient's vascular system, said guidewire section having a matingend adapted to extend out of the patient; b. a guidewire extensionsection having a mating end; and c. connecting means for repetitiveconnections between said main guidewire section and said extensionsection by non-permanent deformation of either of said mating endswhereby said mating end of said extension wire section changes lengthalong its longitudinal axis when connected and disconnected to said mainguidewire section. .Iaddend. .Iadd.24. An extendable guidewire systemfor multiple catheter exchanges, comprising: a. a main guidewire sectionadapted to be inserted into a patient's vascular system, said guidewiresection having a mating end adapted to extend out of the patient; b. aguidewire extension section having a mating end; c. connecting means forrepetitive connections between said guidewire section and said extensionsection by the non-permanent deformation of either of said mating ends;and d. means responsive to relative longitudinal movement of saidconnecting means for yieldably reducing the overall diameter of saidmating end of said extension section. .Iaddend. .Iadd.25. The extendableguidewire system of claim 24 wherein one of said mating ends is made ofelastically deformable material. .Iaddend. .Iadd.26. An extendableguidewire system for multiple catheter exchanges, comprising:a. a mainguidewire section adapted to be inserted into a patient's vascularsystem, said guidewire section having a mating end adapted to extend outof the patient; b. a guidewire extension section having a mating end; c.resilient, selectably releasable connecting means for repetitiveconnections between said main guidewire section and said extensionsection by the non-permanent deformation of either of said mating endswhereby said extension wire section and said main guidewire section canbe repetitively connected and disconnected. .Iaddend. .Iadd.27. Theextendable guidewire system of claim 26 wherein one of said mating endsis made of elastically deformable material. .Iaddend. .Iadd.28. Anextendable guidewire system for multiple catheter exchanges,comprising:a. a main guidewire section adapted to be inserted into apatient's vascular system, said guidewire section having a mating endadapted to extend out of the patient; b. a guidewire extension sectionhaving a mating end; c. connecting means for repetitive connectionsbetween said main guidewire section and said extension section bynon-permanent deformation of either of said mating ends; and d.resilient spring means provided by one of said mating ends for impartinga retaining force to said other mating end after said mating ends arereleasably connected. .Iaddend. .Iadd.29. An extendable guidewire systemfor multiple catheter exchanges, comprising: a. a main guidewire sectionadapted to be inserted into a patient's vascular system, said guidewiresection having a mating end adapted to extend out of the patient; b. aguidewire extension section having a mating end; c. one of said matingends adapted to receive the other mating end to provide a detachableconnection; and d. resilient spring means within said connection forretaining said mating ends in detachable engagement. .Iaddend. .Iadd.30.A method of using an extendable guidewire system in a vascularprocedure, said guidewire system having a main guidewire section with amating end, a guidewire extension section with a mating end, and aconnection therebetween suitable for repetitive connections comprising atubular member having an open end on one of said mating ends of theguidewire sections, a male member on the mating end of the other sectionwhich is adapted to be inserted into the open end of the tubular memberand means to releasably secure the interconnected ends together, themethod comprising the steps of: a. percutaneously introducing a mainguidewire section into the vascular system of a patient with the matingend thereof extending outside the body of the patient; b. advancing afirst catheter over the main guidewire section within the vascularsystem; c. releasably securing the mating end of the extension guidewiresection to the mating end of the main guidewire section by manuallyinserting the male member on one of the guidewire sections into thetubular member on the other guidewire section so that the interconnectedends are releasably secured together by a spring force between said malemember and the inner surface of said tubular member; d. withdrawing thefirst catheter from the vascular system of the patient over the twointerconnected guidewire sections; e. introducing a second catheter intothe patient's vascular system over the two interconnected guidewiresections; and f. disengaging the extension guidewire section from themain guidewire section by manually pulling the two guidewire sectionsapart with the main guidewire section remaining in place in the vascularsystem of the patient. .Iaddend. .Iadd.31. An extendable guidewiresystem for multiple catheter exchanges, comprising:a. a main guidewiresection adapted to be inserted into a patient's vascular system, saidguidewire section having a mating end adapted to extend out of thepatient; b. a guidewire extension having a mating end formed by atubular member; c. connecting means for detachably joining said matingend of said main guidewire section to said mating end of said guidewireextension section; and d. said connecting means having an overallmaximum diameter, after connection, no greater than the maximum diameterof either of said guidewire extension section or main guidewire section..Iaddend.